钢-超高性能混凝土组合箱梁静力性能试验研究与数值模拟

以云南红河特大桥为工程背景，设计2个钢-超高性能混凝土(ultra-high performance concrete，UHPC)组合箱梁节段模型试验，主要关注组合箱梁的承载力、破坏模式和抗裂性能等。基于通用有限元软件ABAQUS建立组合箱梁的精细有限元模型，通过试验结果验证模型并开展参数分析，研究UHPC板厚度、配筋率、栓钉间距以及箱梁横隔板厚度对组合箱梁受力性能的影响，给出各参数的设计建议取值范围。研究结果表明:钢-UHPC组合箱梁承载力高、抗裂性能好；按最大裂缝宽度进行验算，等效为180 mm厚UHPC桥面板的承载力超过车辆荷载标准值的8倍；UHPC板厚度以及钢箱梁横隔板厚度对组合箱梁破坏模式影响较大；综合考虑经济性及受力性能，建议实际工程中UHPC桥面板厚度不宜超过210 mm，配筋率不宜超过1.4%，栓钉间距最大不超过450 mm。

EXPERIMENTAL AND NUMERICAL RESEARCH ON STATIC PERFORMANCE OF STEEL-UHPC COMPOSITE BOX GIRDER

Based on the Yunnan Honghe bridge, two segmental model tests of a steel-UHPC composite box girder were designed. The research focused on bearing capacity, on failure mode and on crack resistance of the composite box girder. The shell element-based finite element models (FEM) were established in ABAQUS and verified by test results. Parameter analysis was carried out to study the influence of UHPC slab thickness, reinforcement ratio, stud spacing and steel beam diaphragm thickness on the mechanical performance of the composite box girder. The design suggestions for each parameter were developed finally. The results show that: the steel-UHPC composite box girders exhibit high bearing capacity and good crack resistance; considering the limitation of maximum crack width, the bearing capacity of the 180 mm-thick equivalent UHPC bridge deck is more than 8 times of the vehicle load standard value; the thickness of UHPC slab and steel beam diaphragm show a great influence on the failure mode of the composite box girder; considering the balance of economy and mechanical performance, the actual thickness of UHPC bridge deck should be 210 mm and below, the reinforcement ratio should be 1.4% and below, and the stud spacing should be 450 mm and below.